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Lucene example source code file (ReqOptSumScorer.java)

This example Lucene source code file (ReqOptSumScorer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

io, ioexception, ioexception, no_more_docs, override, override, reqoptsumscorer, reqoptsumscorer, scorer, scorer

The Lucene ReqOptSumScorer.java source code

package org.apache.lucene.search;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/** A Scorer for queries with a required part and an optional part.
 * Delays skipTo() on the optional part until a score() is needed.
 * <br>
 * This <code>Scorer implements {@link Scorer#skipTo(int)}.
 */
class ReqOptSumScorer extends Scorer {
  /** The scorers passed from the constructor.
   * These are set to null as soon as their next() or skipTo() returns false.
   */
  private Scorer reqScorer;
  private Scorer optScorer;

  /** Construct a <code>ReqOptScorer.
   * @param reqScorer The required scorer. This must match.
   * @param optScorer The optional scorer. This is used for scoring only.
   */
  public ReqOptSumScorer(
      Scorer reqScorer,
      Scorer optScorer)
  {
    super(reqScorer.weight);
    this.reqScorer = reqScorer;
    this.optScorer = optScorer;
  }

  @Override
  public int nextDoc() throws IOException {
    return reqScorer.nextDoc();
  }
  
  @Override
  public int advance(int target) throws IOException {
    return reqScorer.advance(target);
  }
  
  @Override
  public int docID() {
    return reqScorer.docID();
  }
  
  /** Returns the score of the current document matching the query.
   * Initially invalid, until {@link #nextDoc()} is called the first time.
   * @return The score of the required scorer, eventually increased by the score
   * of the optional scorer when it also matches the current document.
   */
  @Override
  public float score() throws IOException {
    int curDoc = reqScorer.docID();
    float reqScore = reqScorer.score();
    if (optScorer == null) {
      return reqScore;
    }
    
    int optScorerDoc = optScorer.docID();
    if (optScorerDoc < curDoc && (optScorerDoc = optScorer.advance(curDoc)) == NO_MORE_DOCS) {
      optScorer = null;
      return reqScore;
    }
    
    return optScorerDoc == curDoc ? reqScore + optScorer.score() : reqScore;
  }

}

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